This reverts commit 02e57873.

Reason for revert: High flakiness and broken GPU builders. See:
https://crbug.com/v8/10178
(speculative revert)

Original change's description:
> heap: Delay completing marking
> 
> Delay completing marking (and thus the atomic GC pause) during JS
> executions, increasing the chance to finalize the garbage collection
> from a task. This is beneficial as it avoids stack scanning which is
> expensive and can keep alive outdated objects in case of unified heap.
> 
> Completing will be delayed at most by some overshoot factor (10%).
> 
> In addition, the GC keeps the weighted average of previously recorded
> time to incremental marking task invocations and bails out if the
> task is expected to arrive too late.
> 
> Bug: chromium:1044630
> Change-Id: I10e63e6aaa88d8488d4415f311016dce2b4e62a2
> Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2030906
> Commit-Queue: Michael Lippautz <mlippautz@chromium.org>
> Reviewed-by: Ulan Degenbaev <ulan@chromium.org>
> Cr-Commit-Position: refs/heads/master@{#66107}

TBR=ulan@chromium.org,hpayer@chromium.org,mlippautz@chromium.org

Change-Id: I0cd3f1189d0f83754350d5bdaaf82cb3c4d402c8
No-Presubmit: true
No-Tree-Checks: true
No-Try: true
Bug: chromium:1044630, v8:10178
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2037434Reviewed-by: Michael Achenbach <machenbach@chromium.org>
Commit-Queue: Michael Achenbach <machenbach@chromium.org>
Cr-Commit-Position: refs/heads/master@{#66120}